Mechanical foam generator



'Dec.19,1939. QMHAMBLIN 2,183,561

I MECHANICAL FOAM GENERATOR Filed March 17, 1938 4 Sheets-Sheei'l 1 INVENTOR BY CLYDE M. HAMBLIN ATTORNEY Dec. 19, 1939. c. M. HAMBLIN IECHANICAL FOAM GENERATOR 4 Sheets-Sheet 2 Filed Marqh 17, 1938 Q %/25 M M INVENTOR BYCLYDE M.HAMBLIN w/zfl;

ATTORNEY Dec. 19, 1939. j, HAMBUN 2,183,561

IECHANICAL FOAM GENERATOR Fil ed March 17, 1938. 4 Sheets-Sheet :s

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45 0 L30 i 46 E 29 25 FIG. ll INVENTOR- BY CLYDE M. HAMBLIN ATTORNEY C. M. HAMBLLIN IECHANICAL FOAM GENERATOR Filed March 1'7, 1938 4 Sheets-Sheet 4' FIG. l2.

INVENTOR BY CLYDE M. HAMBLIN ATTORNEY Patented Dec. 19, 1939 MECHANICAL FOAM GENERATOR Clyde M; Hamhlin, Washington, D. 0. Application March 17, 1938, Serial No. 196,411

6 Claims. (Cl. 261-76) (Granted under the act of March 3, 1883, as

amended April 30, 1928; 370 0.6. 757) This invention relates to improvements in means for mechanical generation of foam for extinguishing fires.

It is a principal object-of this invention to provide means for mechanically mixing water with a foaming agent such as saponine, Tutogen,

such as shown in U. S. Patent No. 2,088,085, or similar liquid and air or inert gas such as 002 or nitrogen to produce a foam as used for extinguishing fires.

Another object ofthis invention is to reduce the cost and weight and the space occupied by stowage of foam ingredients and avoid the size and weight of generating equipment necessary for the chemical generation of foam which is the generally accepted method in this country. In accomplishing these objects there are provided the improved forms of construction shown diagrammatically by the accompanying draw- 'ings,'wherein, Fig. 1 is a sectional view of a foam generator of the Venturi tube type of construction.

Fig. 2 is a sectional view of a generator attachment. 3 shows the fluid valve stems and indicators.

Fig. 4 is a cross-sectional view taken at 4-4 onFig.2.

Fig. 5 is asectional view of a foam generator of the ejector or eductor type of construction.

Fig. 6 is a sectional view of a modified form of ejector or eductor type of foam generator in which a propeller wheel is actuated by the flow of the fluid to beat the mixture to a foam.

Fig. 7 is a sectional view of a modified form of discharge nozzle of Fig. 6.

Fig. 8 is a sectional view 0f a foam generator of the orifice type construction. Fig. 9 is a sectional view of a modified form of orifice'for'the generator shown on Fig. 8.

Fig. 10 is a sectional view of a portion of a modified form of orifice type foam generator.

1' 8. 11 is a sectional view of a portion of another modified iorm of orifice type foam gen- 5 erator.

Fig. 12 is a modified form of foam generator of the Venturi tube type having reentrant passages to aid in generating the foam, and I Fig. 13 isa cross-section of view on line ii-l3 '50 of Fig. 12.

Throughout the description like numbers designate like parts in the various figures.

Referring more in detail to the several drawings: v 55 There is shown in Fig. l aventuri tube having an inlet ill for connecting to a water supply pipe or hose and an outlet II for connecting to a pipe or hose for discharging the foam. The Venturi tube is supported by a base l2. Above the Venturi tube and supported by web I; is a reservoir 8 I 4 for containing the foaming agent. At the top of the reservoir is a filling cap IS with a vent hole It. At the bottom of the reservoir is .a tube l1, fitted with a valve or other adjusting means i8 and connecting to the throat IQ of the Ven- '10 turi tube by means of holes 20 for admitting the foaming agent. Another tube 2| fitted with valve or other adjusting means 22 and also connecting to the. throat IQ of the Venturi tube by means of holes 23, is provided for admitting air or inert gas.

. indicator scales 38. The adjusting means may also be fixed orifices of predetermined size instead of valves. When air at atmospheric pres- 3 sure is used the tube 2| and holes 23 must be of sumcient size or additional openings provided so that the volume of air admitted will be several times the volume of water passing through the generator.

The foaming agent and air or inert gas are mixed with the water to form foam by making the diverging... angle of the discharge nozzle or pipe 24 of such degree as to cause turbulent flow.

The mixing may be increased by providing in the discharge nozzle or pipe inwardly projecting fins or baiiies 25 arranged in staggered relation to increase turbulence of flow and improve the generation of foam. This modification may be adapted to all types of foam generators described I herein.

In Fig. 2 is shown a foamgenerator attachment added to'the generator shown in Fig. 1, and this attachment consists of a casing or tube 26 adapted to be coupled to the discharge nozzle or pipe 24. The tube 26 is provided with a mechanical beater having a paddle wheel 21 mounted on shaft 28 which is housed in bearing 29 supported by radial arms 30 and driven by a screw type impeller 3| located within a tubular extension 32 from an orifice plate 33, and actuated by the flow of the mixture of water, foaming agent and air or inert gas. Additional guide means or bearing is provided if desired by making impeller 3| an easy turning fit in tubular extension 32. Holes 34 are provided as necessary in plate 33 to avoid excessive resistance to flow. If desired, holes 34 may be omitted and holes provided in casing 26 on the discharge side of plate 33, as in Fig. 10, to admit additional air if required to improve the quality of the foam. The above attachment may be added to any type of generator described herein.

In the ejector or eductor type generator shown in Fig. 5 the foaming agent entering through tube I1 and air or inert gas entering through tube 2| are premixed in tube 31 to aerate the foaming agent before it enters the water stream. The larger quantities of air for mixing with the water stream to aid in the production of foam is drawn by induction through holes 38 in ejector or eductor housing 39 and discharge nozzle inlet 40, due to the high velocity of water through auxiliary nozzle 4|.

In the modified form of ejector or eductor type generator shown in Fig. 6, the mixture of water, foaming agent and air or inert gas is beaten to a foam by the propeller wheel 43 mounted on shaft 28 housed in bearing 29 by radial arms 30 and actuated by the flow of water, foaming agent and air or inert gas through discharge nozzle 42. In this generator air or inert gas under pressure may be admitted to the mixture of water and foaming agent through tube 44 instead of obtaining the air by induction through openings 38 in ejector or eductor housing 39.

In Figf'l a beater having a paddle wheel 21 actuated by screw type impeller 3|, as in Fig. 2, is

provided in discharge nozzle 42 instead of thepropeller type beater 43.

In the generator shown in Fig. 8, a plate 45 having an orifice 46 is substituted for the Venturi throat [9 shown in Fig. 1 and the auxiliary ejector or eductor nozzle 4| shown in Figures 5 and 6. The mixing of water, foaming agent and air in this generator is produced by the turbulence clue to the abrupt slowing down of the water stream after passing through orifice 46, and the mixing is aided by the inwardly projecting fins or baffles 25, as in the case of previously described generators. The openings 38 for admission of air are located. close to the downstream side of orifice plate 45 so as to be within the area of low pressure caused by the jet of water at high velocity through orifice 46. In this generator check valves 41 hinged at 48 are provided for air inlet openings 38 and checli valve 49 is provided in inlet tube 37 to prevent escape of liquid through these openings in event of stoppage of the discharge hose. These check valves also permit a pressure to be built up which will tend to clear the stoppage. Instead of a single check Valve 49 in tube 3'! separate check valves may be provided in tubes I'I'and 2|.

Check valves described above may be adapted to the air openings and tubes for admitting the foaming agent and air or inert gas in any of the generators described herein.

In Fig. 9 the orifice plate 45 is modified by having the upstream side streamlined to reduce the resistance to fiow. In this figure the air inlets 38 are provided through plate 45, but they may be provided through casing 24 on the downstream side of the orifice plate, as in Fig. 8.

In Fig. 10 is shown a modification of the orifice plate type of generator in which a paddle wheel 21 driven by screw type impeller 3| actuated by the flow of water through tubular extension 32 in plate 33 is used to beat the mixture of water, foaming agent and air or inert gasito foam.

In this, as in Fig. 8, openings 38 with check valves 41 are shown for admission of air at atmospheric pressure, and check valve is shown to prevent back flow through tube 31.

Fig. 11 is a modification of the orifice type generator shown in Fig. 9, in which a propeller 43 actuated by the jet of water through orifice 46 is used to beat the mixture of water,'foaming agent and air or inert gas to foam.

In Fig. 12 is shown a modification of the Venturi type generator in which the mixing of water, foaming agent and air or inert gas to generate foam is aided by circulating a portion of the liquid mixture through pressure discharge openings 56 at enlargement 5|, tubes 52 and induction inlet openings 53 at throat of venturi 54.

Other modifications and changes in the proportions and arrangements of the parts may be made by those skilled in the art without departing from the nature of the invention, within the scope of what is hereinafter claimed.

The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

Having thus set forth and disclosed the nature of this invention, what is claimed is:

1. An apparatus for the production of fire extinguishing foam comprising a tube having an entrance end and an exit end, a conduit for quenching liquid connected to the entrance end of the tube, a foam promoting agent reservoir, said reservoir being connected to discharge into said tube, said tube having means for gas to enter therein, means in said tube to produce a turbulent mixture of the gas, foam producing agent and quenching liquid, said turbulent mixture producing means comprising a plurality of disconnected staggered vanes extending inwardly from the outlet side of said tube, a. restricted passage, a worm screw in said passage, a spider, a bearing in said spider, a shaft journaled in said bearing, said worm screw being mounted on said shaft at one end thereof and extending into said restricted passage, and a mixing 'wheel of a substantially greater diameter than said worm screw mounted at the other end of said shaft within said tube to beat the turbulent mixture into a foam.

2. An apparatus for the production of fire extinguishing foam comprising a tube having an produce a turbulent mixture of the gas, foam producing agent and quenching liquid, said turbulent mixture producing means comprising a plurality of disconnected staggered vanes extending inwardly from the outlet side of said tube, a worm screw in said passage, a spider, a bearing in said spider, a shaft journaled in said bearing, said Worm screw being mounted on said shaft at one end thereof, and a mixing wheel of a substantially greater diameter than said worm screw mounted at the other end of said shaft within said tube to beat the turbulent mixture into a foam, said means for permitting gas to enter said tube comprising gas inlet openings in said tube on the outlet side of said restricted passage.

3. An apparatus for the production of fire extinguishing foam comprising a tube having an entrance end, a restricted passage and an exit end, a conduit for quenching liquid connected to the entrance end of the tube, a foam promoting agent reservoir, said reservoir beingconnected to discharge into said tube, said tube having means for gas to enter therein, means in'said tube to produce a turbulent mixture of the gas, foam producing agent and quenching liquid, said tur- 3 bulent mixture producing means comprising a plurality of disconnected staggered vanes extending inwardly from the outlet side of said tube, a worm screw in said passage, a spider, a bearing in said spider, a shaft journaled in said bearing, said worm screw being mounted on said shaft at one end thereof, a mixing wheel of a substantially greater diameter than said worm screw mounted at the other end of said shaft within said tube to beat the turbulent mixture into a foam, said means for permitting gas-to enter said tube comprising gas inlet openings in said tube on the outlet side of said restricted passage, and flap check valves preventing escape of back pressure through said gas inlet opening.

4. An apparatus for the production of fire extinguishing foam comprising a tube having an entrance end, a restricted passage and an exit end, a conduit for quenching liquid connected to the entrance end of the tube, a foam promoting agent reservoir, one way check valved means connecting said reservoir to discharge into said tube, said tube having means for gas to enter therein, means in said tube to produce a turbulent mixture of the gas, foam producing agent and quenching liquid, said means for permitting gas to enter said tube comprising gas inlet openings in said tube on the outlet side of said restricted passage, and flap check valves preventing escape of back pressure through said gas inlet openings.

5. An apparatus for the production of fire extinguishing foam comprising a tube having an entrance end, a restricted passage and an exit end, a conduit for quenching liquid connected to the entrance end of the tube, a foam promoting agent 1 eservoir, one way check valved means connecting said reservoir to discharge into said tube, said 'vanes extending inwardly from the outlet side of said tube, said means for permitting gas to enter quenching liquid, a restricted passage, a' worm screw in said passage, a spider, a bearing in said spider, a, shaft journaled in said bearing, said worm screw being mounted on said shaft at one end thereof, and a mixing wheel of a substantially greater diameter than said worm screw mounted at the other end of said shaft within said tube to beat the turbulent mixture into a foam.

CLYDE M. HAMBLIN.

mixture of the gas, foam producing agent and 

